SPRINGFIELD, Mo. — As of Tuesday, AT&T is shutting down its 3G network, causing multiple technology devices to not work the same.

“All of the cellular phones that are using different frequencies, you have to get rid of the older ones, before you can get new ones,” said Xiang Guo, Missouri State University Assistant Professor, Department of Information Technology and Cybersecurity.

Those in emergency communications departments hope people are aware certain devices may no longer work, affecting some people’s ability to get in touch with authorities.

“It’s something that people definitely need to be aware of,” said Kris Inman, Director of Springfield, Greene County 9-1-1. “We are in the business of making contacting us as simple and quick as possible.”

Inman said it’s important to reach out to the different cellular companies if people have questions about their devices working properly.

“When you have older phones, like the flip phones, or iPhone 5, I know certain people don’t want to get new things, they just say I really like my phone I don’t wanna change, but if the carrier phases out the 3G spectrum, that means your phone no longer works,” said Guo.

If you’re not sure which network your phone is on, open Settings, tap Network, and Internet and then select Mobile Network on Android devices. On iOS, choose Settings, Cellular, and then pick Cellular Data Options. 

Tech experts said the change isn’t just affecting phones.

“There may be certain medical devices, or tablets, or as I mentioned earlier, smartwatches, vehicle SOS services, home security systems,” said Inman. “So many different items that you use are connected in some way.”

Guo said there is some workaround to have devices use WiFi instead, but getting new technology might be a good idea due to better security. 

“It’s always like it’s a tug of war, but just think about newer technology comes with newer capabilities,” said Guo. “They’re probably designed to be more secure.”

AT&T has published a detailed list of phones and digital devices that will still work after their 3G switch off, as well as devices that may require a software update to enable HD voice, Wi-Fi Calling, Video Call, Advanced Messaging or 5G services.

T-Mobile and Verizon also plan to end 3G services in the coming months.